Antibacterial compounds

ABSTRACT

Esters of an acid of formula: ##STR1## which is termed &#34;monic acid&#34; have activity against Gram-positive and Gram-negative organisms.

CROSS-REFERENCE

This is a division of Ser. No. 872,806 filed Jan. 27, 1978 which is aDivisional of U.S. Ser. No. 803,466, filed June 6, 1977, now U.S. Pat.No. 4,102,901 granted July 25, 1978.

This invention relates to antibacterial compounds and in particular to aclass of esters which have antibacterial activity against certainGram-positive and Gram-negative organisms, in particular Haemophilisinfluenzae and Neisseria gonorrhoae; and also possess goodantimycoplasmal activity. The compounds are therefore of value in thetreatment of veterinary bacterial infections and of particular value inhumans in the treatment of bronchitis and venereal disease.

The routine treatment for gonorrhoae has for many years been the use ofpenicillin antibiotics. However, some strains of gonococci are lesssensitive to penicillins and the degree of such resistance has graduallyincreased resulting in larger doses of penicillins being required.Furthermore there have been reports of strains which producepenicillinase, and are thus highly resistant to penicillin therapy. TheBritish Medical Journal (1976) at page 963 comments: "Now the outlookfor the control of gonorrhoae has been radically changed for the worseby the portentous announcement of the existence of frankly resistantstrains owing their resistance to the production of penicillinase, thepenicillin-destroying enzyme found by many other bacterial species. Thisis wholly a new development, the consequences of which might well bedisastrous".

This invention is concerned with a class of compounds which have highactivities against many organisms including N. gonorrhoae, and as thecompounds are completely unrelated to the β-lactam type of antibiotics(including penicillins and cephalosporins), they are completelyunaffected by penicillinase.

Pseudomonic acid has the structure (I): ##STR2## and is disclosed ashaving antibacterial activity in British Pat. No. 1,395,907. It has nowbeen found that other esters of the allylic carboxylic acid moiety ofthe molecule also retain antibacterial activity.

Accordingly, the present invention provides a compound of formula (II):##STR3## wherein R represents a pharmaceutically acceptableester-forming radical, provided that R is not a group of formula--(CH₂)₈ CO₂ H or an ester thereof.

The corresponding compound of formula (II) wherein R is hydrogen isdescribed in our co-pending Application of even date. That compound inwhich the double bond is in the E configuration, we have designated"monic acid" and it will be referred to as such in this specification.The corresponding Z-isomer is termed "isomonic acid". It is believedthat monic acid has the absolute stereochemistry as shown in formula(IIA): ##STR4## (The numbering is shown for the tetrahydropyran ring).

Suitable ester-forming radicals for the group R include:

(a) C₁₋₂₀ alkyl, C₂₋₈ alkenyl or C₂₋₈ alkynyl each of which may beoptionally substituted by C₃₋₇ cycloalkyl, halogen, carboxy, C₁₋₆alkoxycarbonyl, carbamoyl, aryl, heterocyclyl, hydroxy, C₁₋₆alkanoyloxy, amino, mono- and di- (C₁₋₆) alkylamino;

(b) C₃₋₇ cycloalkyl optionally subsituted with C₁₋₆ alkyl;

(c) aryl;

(d) heterocyclyl.

The term "aryl" includes phenyl, and naphthyl optionally substitutedwith up to five halogen, C₁₋₆ alkyl, C₁₋₆ alkoxy, halo(C₁₋₆)alkyl,hydroxy, amino, carboxy, C₁₋₆ alkoxycarbonyl or C₁₋₆alkoxycarbonyl(C₁₋₆)alkyl groups.

The term "heterocyclyl" includes single or fused rings comprising up tofour hetero atoms in the ring selected from oxygen, nitrogen and sulphurand optionally substituted with up to three halogen, C₁₋₆ alkyl, C₁₋₆alkoxy, halo(C₁₋₆)alkyl, hydroxy, amino, carboxy, C₁₋₆ alkoxycarbonyl,C₁₋₆ alkoxycarbonyl(C₁₋₆)alkyl, aryl or oxo groups.

One suitable substituted alkyl group for the group R has the formula(III):

    --(CH.sub.2).sub.n CO.sub.2 R.sup.1                        (III)

wherein n is an integer from 1 to 7 or 9 to 20 and R¹ is hydrogen or apharmaceutically acceptable salt-forming ion or C₁₋₆ alkyl.

Another sub-class of esters of formula (II) comprises those compoundswherein the group R has the formula (IIIA): ##STR5## wherein n is zeroor 1 to 20, R² is C₁₋₆ alkyl, and Q represents phenyl, C₁₋₆ alkyl, C₃₋₇cycloalkyl, C₁₋₆ alkoxycarbonylmethyl, benzyl, trifluoromethylbenzyl,halobenzyl.

Preferably, within formula (IIIA) n is zero or 1 to 3, R² is methyl andQ is phenyl, methyl, iso-propyl, n-hexyl, cyclohexyl,methoxycarbonylmethyl, benzyl, 3-trifluoromethylbenzyl.

Thus the group R in compound (II) may be for example C₁₋₆ alkyl, inparticular, methyl, ethyl n- or iso-propyl, n-, sec-, iso- ortert-butyl; halo-(C₁₋₆)-alkyl such as trifluoromethyl, 2-chloroethyl,2,2,2-trichloroethyl; aminoalkyl groups such as aminoethyl,2-aminoethyl; hydroxymethyl, 2-hydroxyethyl; phenyl; substituted phenyl;a benzyl group; or a group of formula (III) wherein n is an integer from1 to 7.

Other specific examples of the group R include: C₇₋₂₀ alkyl groups suchas heptyl, octyl, nonyl, decyl and dodecyl, cyclopropyl,cyclopropylmethyl, cyclopentyl, cyclohexyl, methoxycarbonylmethyl,2-methoxycarbonylethyl, 3-methoxycarbonylpropyl,4-methoxycarbonyl-n-butyl, 5-methoxycarbonyl-n-pentyl,6-methoxycarbonyl-hexyl, 7-methoxycarbonyl-n-heptyl,10-methoxycarbonyldecyl, carbamoylmethyl, benzyl, 2,4,6-trichlorophenyl,pentachlorophenyl, o- or m; or p-methylphenyl, o-, m- orp-methoxycarbonylphenyl, 2- or 3- or 4-pyridyl, prop-2-enyl,prop-2-ynyl, 2-dialkylaminoethyl, or 3-methoxycarbonylprop-2-enyl.

Further specific groups R include the following: ##STR6##

The compounds of this invention incorporate a trisubstituted double bondand may therefore exist in both the E (the natural) and Z (or iso)geometrical forms. It is to be understood that both geometrical isomersof any compound of formula (II) are included with the scope of thisinvention, as well as mixtures of the two isomers. However, because ingeneral the E-isomer of a particular structure has the greater activity,it is preferable to employ that isomer.

The compounds of the present invention may be prepared from theintermediate ketone of formula (IV) by any method known to convert aketone into an α,β-unsaturated ester. One such process comprisesreacting a compound of formula (IV), in which the hydroxyl groups may beprotected with a compound of formula (IV) or (VI): ##STR7## in whichformulae (V) and (VI) the symbols R_(a), R_(b) and R_(c) are the same ordifferent and each is lower alkyl, aryl or aralkyl, and R is as definedwith respect to formula (II) above; and subsequently removing anyhydroxyl protecting groups.

The preferred embodiment of this process comprises reacting compound(IV) with compound (V). Preferably, in this case R_(a) and R_(b) aremethyl or ethyl. In the case when compound (IV) is reacted with compound(VI), then R_(a), R_(b), and R_(c) are preferably all phenyl.

The reaction is usually carried out in an inert solvent such asdimethylformamide, hexane, benzene, tetrahydrofuran for example, at atemperature of from about 10° C. to about 100° C. preferably under aninert gas such as nitrogen. Under these conditions the reaction proceedssmoothly over a period of from a few minutes to a few hours and theproduct may be isolated by any of the usual techniques, e.g. solventevaporation or anti-solvent precipitation followed by filtration. Inmany cases the reaction may be carried out in a solvent in which theproduct is insoluble and in such cases the precipitation solid may becollected by filtration. Purification of the product may be by any ofthe usual chromatographic or recrystallisation techniques.

Prior to the above process of this invention, it may be desirable toprotect the hydroxyl groups in compound (IV). Although the reaction withthe compound (V) or (VI) is possible without hydroxyl protection, ingeneral higher yields of the product (II) are formed if the hydroxylgroups are protected. Again, such protecting groups must be removableunder suitably mild conditions and suitable groups include silyl groupsproduced from a silylating agent as discussed above. Particularlysuitable hydroxyl-protecting groups include trimethylsilyl,t-butyldimethylsilyl, methylthiomethyl. A preferred hydroxyl-protectinggroup is trimethylsilyl, as it is readily removed on completion of thereaction.

The compounds (II) may also be prepared by reacting the ketone offormula (IV) with:

(a) an ethynyl ether of formula (VII):

    HC.tbd.C--OR                                               (VII)

wherein R is as defined above with respect to formula (II) andsubsequently treating the product with acid;

(b) an α-lithium carboxylic acid derivative of formula (VIII): ##STR8##wherein R is as defined above with respect to formula (II), and R^(y) isa silyl group, preferably trimethylsilyl;

(c) a malonic acid derivative of formula (IX): ##STR9## wherein R is asdefined above with respect to formula (II), in the presence of titaniumchloride and pyridine;

(d) a reagent to convert compound (IV) to an enamine and subsequentlyreacting the enamine with a malonic acid derivative of formula (X):##STR10## wherein R is as defined above with respect to formula (II).Compounds of formula (II) may also be prepared by esterification ofmonic acid or isomonic acid or a salt or other reactive derivative ofthe acid or transesterification of a compound of formula (II) wherein Ris a different ester-forming radical. Esterification may be performed byany conventional method for example by reaction of the free acid:

(a) with the appropriate alcohol in the presence of a catalyst such as astrong acid, dry hydrogen chloride, or p-toluenesulphonic acid or

(b) with the appropriate halide or sulphate of the alcohol in thepresence of dimethylsulphoxide and calcium carbonate or with the halidein the presence of hexamethylphosphoramide; or

(c) by phase transfer catalysis methods with the halide and/or sulphateof the alcohol in aqueous and/or organic solution in the presence of aquaternary ammonium salt such as tetrabutyl ammonium bisulphate orhalide, or benzyltrimethyl-ammonium halide; or

(d) with a diazoalkane.

The formation of compounds (II) may also be carried out by conventionaltransesterification methods, for example reaction of an ester with theappropriate alcohol in the presence of a catalyst such as the sodiumsalt of the alcohol or dry hydrogen chloride, p-toluenesulphonic acid,or potassium cyanide. This process includes, of course, thetransesterification of pseudomonic acid and esters thereof.

The compound of formula (IV) and its preparation is disclosed in Ser.No. 803,467 filed June 6, 1977, now U.S. Pat. No. 4,102,904.

The antibiotic compounds according to the invention may be formulatedfor administration in any convenient way for use in human or veterinarymedicine, by analogy with other antibiotics, and the invention thereforeincludes within its scope a pharmaceutical composition comprising acompound of formula (II) above together with a pharmaceutical carrier orexcipient.

The compositions may be formulated for administration by any route, andwould depend on the disease being treated. The compositions may be inthe form of tablets, capsules, powders, granules, lozenges, or liquidpreparations, such as oral or sterile parenteral solutions orsuspensions.

Tablets and capsules for oral administration may be in unit dosepresentation form, and may contain conventional excipients such asbinding agents, for example syrup, acacia, gelatin, sorbitol,tragacanth, or polyvinyl-pyrollidone; fillers, for example lactose,sugar, maize-starch, calcium phosphate, sorbitol or glycine; tablettinglubricants, for example magnesium stearate, talc, polyethylene glycol orsilica; disintegrants, for example potato starch; or acceptable wettingagents such as sodium lauryl sulphate. The tablets may be coatedaccording to methods well known in normal pharmaceutical practice. Oralliquid preparations may be in the form of, for example, aqueous or oilysuspensions, solutions, emulsions, syrups, or elixirs, or may bepresented as a dry product for reconstitution with water or othersuitable vehicle before use. Such liquid preparations may containconventional additives such as suspending agents, for example sorbitol,syrup, methyl cellulose, glucose syrup, gelatin, hydroxyethylcellulose,carboxymethyl cellulose, aluminium stearate gel or hydrogenated ediblefats, emulsifying agents, for example lecithin, sorbitan monooleate, oracacia; non-aqueous vehicles (which may include edible oils), forexample almond oil, fractionated coconut oil, oily esters such asglycerine, propylene glycol, or ethyl alcohol; preserivatives, forexample methyl or propyl p-hydroxybenzoate or sorbic acid, and ifdesired convention flavouring or colouring agents.

Suppositories will contain conventional suppository bases, e.g. cocoa,butter or other glyceride.

For parenteral administration, fluid unit dosage forms are preparedutilizing the compound and a sterile vehicle, water being preferred. Thecompound, depending on the vehicle and concentration used, can be eithersuspended or dissolved in the vehicle. In preparing solutions thecompound can be dissolved in water for injection and filter sterilizedbefore filling into a suitable vial or ampoule and sealing.Advantageously, adjuvants such as a local anesthetic, preservative andbuffering agents can be dissolved in the vehicle. To enhance thestability, the composition can be frozen after filling into the vial andthe water removed under vacuum. The dry lypophilized powder is thensealed in the vial and an accompanying vial of water for injection issupplied to reconstitute the liquid prior to use. Parenteral suspensionsare prepared in substantially the same manner except that the compoundis suspended in the vehicle instead of being dissolved and sterilizationcannot be accomplished by filtration. The compound can be sterilized byexposure to ethylene oxide before suspending in the sterile vehicle.Advantageously, a surfactant or wetting agent is included in thecomposition to facilitate uniform distribution of the compound.

The compositions may contain from 0.1% to 99% by weight, preferably from10-60% by weight, of the active material, depending on the method ofadministration. Where the compositions comprise dosage units, each unitwill preferably contain from 50-500 mg., of the active ingredient. Thedosage as employed for adult human treatment will preferably range from100 to 3000 mg., per day, for instance 1500 mg., per day, depending onthe route and frequency of administration.

The following Examples illustrate this invention.

EXAMPLE 1 Preparation of Ethyl4-[3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2-enoate,E and Z isomers (ethyl monate and ethyl isomonate)

(a) Preparation of2S-Acetonyl-3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran

(Compound A) ##STR11## Ozonised oxygen (ca 1%) was bubbled through asolution of methyl pseudomonate (0.514 g) in methanol (8 ml) andpyridine (2 drops) at -78° C. for 0.5 hour (when blue colour developed).The excess ozone was blown off by dry nitrogen at -78° C. Triethylphosphite (80%. 0.3 ml) was then added and the reaction mixture wasallowed to come to room temperature. The solvent was removed at roomtemperature in vacuo and the residue was chromatographed over silica gel(20 g). Elution of the column with chloroform-methanol (93:7) at therate of 2 ml min⁻¹ gave the title compound (0.299 g), m.p. 85°-86° (fromchloroform), [α]_(D) ²⁰ +11.9° (c, 1.0, CHCl₃), νmax. (CHCl₃) 1708,1112, 1080, and 1050 cm⁻¹. (b) Condensation of ketone A with triethylphosphonoacetate with protection of hydroxy-groups

Bistrimethylsilylacetamide (0.25 ml, 1 mmole) was added to a solution of2-acetonyl-3,4-dihydroxy-5-(2,3-epoxy-5-hydroxy-4-methylhexyl)-2,3,5,6-tetrahydropyran(0.1 g, 0.33 mmole) in tetrahydrofuran (1 ml) at 0° C. and then stirredat room temperature for 0.5 hour. The solvent was then completelyremoved in vacuo at room temperature and the residue dissolved intetrahydrofuran (1 ml) for use in the next stage. Triethylphosphonoacetate (0.075 g, 0.33 mmole) in tetrahydrofuran (2 ml) wasadded dropwise to a stirred suspension of sodium hydride (0.01 g, 80%dispersion in oil) in tetrahydroduran (2 ml) at 0° under nitrogen over15 min. The reaction mixture was then stirred under nitrogen at roomtemperature for 1 hour. The solution of silylated2-acetonyl-3,4-dihydroxy-5-(5-hydroxy-2,3-epoxy-4-methylhexyl)-2,3,5,6-tetrahydropyranwas then added dropwise over 15 min. to the reaction mixture kept at 0°.This was then kept at 60° for 15 min. The reaction mixture was pouredinto ice-water (3 g) and acidified to pH 2, keeping the solutionhomogeneous by the addition of ethanol. After 2 min aqueous sodiumbicarbonate (10 ml) was added and the mixture was saturated with sodiumchloride and extracted continuously with ether. The ethereal extract wasdried and evaporated to give a mixture showing some starting materialand two major products on tlc. Preparative tlc (developed three times bychloroform-methanol (93:7) separated these products into two bands, A(Rf=0.45) and B (Rf=0.40). Extraction of Band A with ethyl acetate (100ml) afforded ethyl4-[3,4-dihydroxy-5-(2,3-epoxy-5-hydroxy-4-methylhexyl)-2,3,5,6-tetrahydropyran-2-yl)-3-methylbut-2Z-enoate(0.021 g), λmax 221 (εm 9,700)nm; νmax (CHCl₃) 1690, 1640, 1262, 1155,1085, and 1060 cm⁻¹ ; δH (CDCl₃) 5.93 (1H, m, -CH═), 4.25 (2H, q, J=7Hz, -CO₂ CH₂ CH₃), 2.06 ##STR12## 1.30 (3H, t, J=7 Hz, --CO₂ CH₂ CH₃),1.25 (3H, d, J=7 Hz, CH₃ CH), and 0.96 (3H, d, J=7 Hz, CH₃ CH); m/e(relative intensity) 372 (M+, 0.5), 354 (1), 336(2), 327(2), 309(4),291(9), 227(100), 224(69), and 209(23) (Found: C, 61.85; H, 9.20%. C₁₉H₃₂ O₇ requires C, 61.25; H, 8.65%). Extraction of Band B with ethylacetate gave ethyl4-[3,4-dihydroxy-5-(2,3-epoxy-5-hydroxy-4-methylhexyl)-2,3,5,6-tetrahydropyran-2-yl)-3-methylbut-2E-enoate(0.069 g), [α]_(D) --1.44° (c, 1.8 CHCl₃); λmax 220 (εm 11,100) nm: νmax(CHCl₃) 1705, 1650, 1155, and 1050 cm⁻¹ ; δH (CDCl₃) 5.86 (1H, m,--CH═), 4.23 (2H, q, J=7 Hz, --CO₂ CH₂ CH₃), 2.70-2.90 ##STR13## 1.30(3H, t, J=7 Hz, --CO₂ CH₂ CH₃), 1.25 (3H, d, J=7 Hz, CH₃ CH), and 0.95(3H, d, J=7 Hz, CH₃ CH); m/e (relative intensity) 372 (M+, 2), 354(2),354(2), 336(3), 327(6), 309(7), 291(6), 270(11), 264(13), 245(10),244(10), 227(100), 224(30), and 209(35) (Found: M+ 372.2150 C₁₉ H₃₂ O₇requires M+ 372.2148).

EXAMPLE 2 Ethyl monate and Ethyl isomonate: Condensation of ketone Awith triethylphosphonoacetate without protection of the hydroxy-groups

Triethyl phosphonoacetate (1.09 ml) in tetrahydrofuran (3 ml) was addeddropwise to a stirred suspension of sodium hydride (0.086 g., 80%dispersion in oil) in tetrahydrofuran (2 ml) at 0° C. under nitrogenover 15 min. The reaction mixture was then stirred under nitrogen atroom temperature for 1 hour. A solution of2-acetonyl-3,4-dihydroxy-5-(5-hydroxy-2,3-epoxy-4-methylhexyl)-2,3,5,6-tetrahydropyran(0.271 g) in tetrahydrofuran (2 ml) was added dropwise over 15 min., tothe reaction mixture kept at 0° C. This was then kept at 60° C. for 1.5hour. The reaction mixture was poured into ice-water (20 ml) which wasthen saturated with sodium chloride. The organic layer was separated andthe aqueous layer washed with ethyl acetate (2×30 ml). The combinedorganic extract was washed with brine (50 ml), dried, and evaporated togive an oil which was filtered through a column of silica gel (30 g).Elution of the column with 2% methanol in chloroform (200 ml) followedby 4% methanol in chloroform (300 ml) at the rate of 1.5 ml min⁻¹afforded 2 fractions. The first fraction was a complex mixture which wasfurther purified by preparative tlc (developed 3 times with 8% methanolin chloroform) to give ethyl4-[3,4-dihydroxy-5-(2,3-epoxy-5-hydroxy-4-methylhexyl)-2,3,5,6-tetrahydropyran-2-yl]-3-methylbut-2Z-enoate(0.017 g) (ethyl isomonate). The second fraction was ca 85% pure(h.p.l.c.) which was further purified by preparative tlc (developed 3times with 8% methanol in chloroform) to give ethyl4-[3,4-dihydroxy-5-(2,3-epoxy-5-hydroxy-4-methylhexyl)-2,3,5,6-tetrahydropyran-2-yl]-3-methylbut-2E-enoate(0.047 g). (ethyl monate)

EXAMPLE 3 Preparation of Methyl4-[3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methyl-but-2-enoate,E and Z isomers (methyl monate and methyl isomonate)

Bistrimethylsilylacetamide (5.9 ml) was added to a solution of 2-acetonyl-3,4-dihydroxy-5-(2,3-epoxy-5-hydroxy-4-methylhexyl)-2,3,5,6-tetrahydropyran(1.204 g) in acetonitrile (25 ml) at room temperature and the mixturewas stirred at room temperature for 1 hour. The solvent was thencompletely evaporated in vacuo at 40° C. and the residue was dissolvedin N,N-dimethylformamide (3 ml) for use in the next stage. Trimethylphosphonoacetate (3 g) in N,N-dimethylformamide (10 ml) was addeddropwise over 0.5 h to a suspension of sodium hydride (80% dispersion inoil, 0.45 g) in N,N-dimethylformamide (10 ml) at 0° C. under a nitrogenatmosphere. The reaction mixture was then stirred under nitrogen at roomtemperature for 1 hour. The solution of silylated ketone was then addeddropwise over 0.5 hour, to the reaction mixture at 0° C. under nitrogenwhich was then stirred at room temperature for 18 hours. The reactionmixture was poured into saturated brine (50 ml) and extracted with ethylacetate (3×50 ml). The organic extract was dried and evaporated to givean oil which was dissolved in dioxane-water (4:1, 25 ml) and treatedwith hydrochloric acid (5 M, 2 drops) for 10 min. Aqueous sodiumbicarbonate (20 ml) was then added and the mixture extracted with ethylacetate (3×30 ml). The organic extract was dried and evaporated to givean oil (1.2 g) which was chromatographed over silica gel (35 g). Elutionof the column with chloroformmethanol (97:3) afforded 2 fractions. Thefirst fraction was further purified by preparative tlc [developed withchloroform: methanol (92:8)] to give methyl isomonate (0.16 g) theZ-isomer as an oil. λmax (EtOH) 222 (ε_(m) 9,600) nm, νmax (CHCl₃) 1695,1645, 1220 (broad), 1155, 1110, 1080, and 1050 cm⁻¹. The second fractionafforded methyl monate (0.4 g), the E-isomer m.p. 121-122 from methylacetate-hexane), [α]_(D) ²⁰ --11.07° [C, 1.5 (CHCl₃)], λmax (EtOH) 221(ε_(m) 14,700) nm, νmax (CHCl₃), 1710, 1645, 1435, 1220 (broad), 1155,1110, and 1050 cm⁻¹.

EXAMPLE 4 Preparation of4-[3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoicacid (monic acid) (a) From Pseudomonic Acid (without protection)

Sodium pseudomonate (10 mg) and potassium carbonate (15 mg) wasdissolved in water (2 ml). The resulting solution was heated to 60° C.and the reaction monitored by analytical high pressure liquidchromatography which after 11/2 hours showed that optimum conversion tomonic acid had occurred. To confirm the presence of monic acid, thereaction mixture was cooled, diluted with water (3 ml) saturated withsodium chloride, layered with ethyl acetate (10 ml) and the pH adjustedto 2.0 with rapid stirring. The organic layer was separated and theaqueous phase re-extracted with ethyl acetate (2×10 ml). The colourlessethyl acetate extracts were combined, treated with excess etherealdiazomethane and evaporated to dryness. The resulting mixture of esterswere examined by h.p.l.c. in several solvent systems. The major peaks inthe chromatogram were shown to have identical retention times withauthentic samples of methyl monate and methyl pseudomonate, therebyconfirming the presence of monic acid together with starting pseudomonicacid in the hydrolysate.

(b) From Methyl Monate

A solution of methyl monate (10 mg) in methanol (0.5 ml) was added to asolution of potassium carbonate (15 mg) in water (0.5 ml). The combinedsolution was heated to 60° C. After 1/2 hour, comparison of peakretention times with authentic monic acid by h.p.l.c. analysis confirmedthe presence of monic acid in hydrolysate.

EXAMPLE 5 Preparation of monic acid from ketone A by Wittig condensation(i) Diethyl carboxymethylenephosphonate

Triethyl phosphonoacetate (44.8 g, 0.2 M) was dissolved in 1 N sodiumhydroxide solution (200 ml; 0.2 M) and stirred at room temperatureovernight. The pH was adjusted from 9.0 to 1.0 with dilute hydrochloricacid. The solution was saturated with sodium chloride and extracted withethyl acetate (3×100 ml). The latter was washed with saturated brine,dried over magnesium sulphate, filtered and evaporated to dryness invacuo to give a viscous, colourless oil, which crystallized to a whitesolid when kept below room temperature (37.4 g; 96%). Thin layerchromatography revealed one component in chloroform at Rf=0.02 asvisualised with iodine vapour. n_(D) ²³ =1.3900.δ (CDCl₃) 9.33 (1H, s,CO₂ H), 4.07 (4H, octet, Me-CH₂ -O-P, J_(HH) =6 Hz, J_(HP) =8 Hz), 2.88(2H, d, P-CH₂ -CO₂ H, J_(HP) =22 Hz) and 9.25 (6H, t, CH₃ -CH₂, J=6 Hz).Irradiation at δ 9.25 produces a doublet at 4.07 with J_(HP) =8 Hz,νmax(film) 1730 (C═O Str.), 1230 (P═O str.), 1170 (P-O vib.), 1050 (P-Ovib.) cm⁻¹. (Found: C, 37.10; H, 7.07; P, 15.66%; C₆ H₁₃ PO₅ requires C,36.74; H, 6.69; P, 15.79%).

(ii) Monic acid

N,O-Bistrimethylsilylacetamide (1.52 ml; 6 mM) was added to a solutionof2-acetonyl-3,4-dihydroxy-5-(5-hydroxy-2,3-epoxy-4-methylhexyl)-2,3,5,6-tetrahydropyran(302 mg; 1 mM) in dry acetonitrile (6 ml). The solution was stirred atroom temperature for 1 hour followed by evaporation to dryness in vacuoat 40° C. The oily residue was dissolved in dry dimethylformamide (6 ml)for use in the next stage. Sodium hydride (114 mg; 80% pure; 3.8 mM) wasadded portionwise over 1/2 hour to a solution of diethylcarboxymethylene phosphonate (392 mg; 2 mM) in dry dimethylformamide (5ml) at 0° under dry nitrogen. The mixture was stirred at 0° C. for afurther 2 hours. The solution of the silylated ketone above was addeddropwise to this mixture at 0° C. under nitrogen and the resultingreaction mixture stirred overnight at room temperature. The latter wasevaporated to dryness and the dark residue dissolved in water (10 ml)and ethanol (10 ml) and the pH adjusted to 1.8. After 5 min., at roomtemperature the solution was diluted with water (15 ml) saturated withsodium chloride and extracted with ethyl acetate (4×10 ml). The latterwas washed with brine, dried over magnesium sulphate, filtered andevaporated to dryness in vacuo to give monic acid. A sample of theresulting oil mixture was dissolved in ethyl acetate and treated withdiazomethane, thus converting the monic acid present into methyl monate.The presence of the latter was confirmed by 4 analytical h.p.l.c.comparisons with authentic pure methyl monate.

EXAMPLE 6 Preparation of Benzyl4-[3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoate(benzylmonate)

Bistrimethylsilylacetamide (3 ml) was added to a solution of2-acetonyl-3,4-dihydroxy-5-(2,3-epoxy-5-hydroxy-4-methyhexyl)-2,3,5,6-tetrahydropyran(0.604 g, 2 mM) in dry acetonitrile (10 ml) and the mixture was stirredat room temperature for 1 hour. The solvent was then completely removedin vacuo at 40° C. and the residue dissolved in dimethylformamide (5 ml)for the next stage.

Diethyl benzyloxycarbonylmethylenephosphonate (2.30 g; 8 mM) in drydimethylformamide (5 ml) was added dropwise to a suspension of sodiumhydride (80% dispersion in oil, 0.240 g; 8 mM) in dry dimethylformamide(5 ml) at 0° C. under nitrogen. The solution was stirred under nitrogenat room temperature for 1 hour. The solution of silylated ketone wasthen added dropwise over 0.5 hour, to the reaction mixture at 0° C.under nitrogen, which was then stirred at room temperature for 18 hours.The solution was evaporated to dryness and the residual yellow oildissolved in ethyl acetate, washed with brine and evaporated to an oil.The latter was dissolved in dioxan/water (4:1; 10 ml) and concentratedhydrochloric acid added to pH 1.5 followed by stirring at roomtemperature for 10 minutes. Excess sodium bicarbonate solution was addedand the mixture was then extracted with ethyl acetate which was washedwith brine, dried over magnesium sulphate, filtered and evaporated to anoil (1.615 g). This oil was chromatographed on silica (40 g) elutingwith gradient of methanol/chloroform 1% to 3%. The fractions containingpure benzyl monate (by hplc and tlc) were collected and evaporated to anoil (0.150 g), [α]_(D) ²⁰ -5.0° (c,1.0 CHCl₃). λmax (EtOH) 219 (εm14,000)nm; νmax (CHCl₃), 3,400 (broad, OH's), 1710 (broad, C═O's), 1645cm⁻¹ ; δH (CDCl₃) 7.26 (5H, s, Ph), 5.75 (1H, s, CH═C), 5.08 (2H, s,PhCH₂), 2.70 ##STR14## 1.17 (3H, d, J=7 Hz, CH--CH₃) and 0.88 (3H, d,J=7 Hz, CH--CH₃); m/e 506 (M+), 488, 444, 91. (Found: M=434.229970 C₂₄H₃₄ O₇ requires 434.230435).

EXAMPLE 74-[3R,4R-Dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoicacid (Monic Acid) (with protection)

Pseudomonic acid (10 g; 20 mM) was dissolved in trimethyl orthoformate(50 ml). p-Toluenesulphonic acid (20 mg) was added and the solution wasstirred at room temperature for 1/2 hour, followed by evaporation todryness in vacuo. The resulting oil was dissolved in 1 N sodiumhydroxide solution (100 ml; 100 mM) and the solution stirred at 65° C.for 2 hours. After completion of the hydrolysis (hplc) the solution wascooled and the pH adjusted to 7.0 with hydrochloric acid. Methanol (75ml) was added, the pH was adjusted to 2.0 with 5 N hydrochloric acid andthe reaction mixture stirred at room temperature for 0.25 hour. The pHwas re-adjusted to 9-9.5 with sodium hydroxide solution and maintaineduntil complete hydrolysis of the O-formate (c.a. 3 hours at roomtemperature; hplc). The pH was adjusted to 7.0 and the solutionevaporated to small bulk (10-20 ml), saturated with sodium chloridelayered with ethyl acetate and with stirring the pH was adjusted to 3.0.The ethyl acetate layer was separated, washed with saturated brine,dried over magnesium sulphate and evaporated to an oil, which wasdissolved in water by addition of 1 N sodium hydroxide solution to pH7.5. The resulting solution of sodium monate and sodium9-hydroxynonanoate was evaporated to dryness in vaco (12.64 g). Thissolid was extracted with ethanol (2×50 ml) and filtered. The ethanolfiltrate was evaporated to dryness to give sodium monate (9.62 g) as awhite solid. The latter was dissolved in water with ethyl acetate andacidified to pH 3.0. The ethyl acetate extract was washed with saturatedbrine, dried over magnesium sulphate and evaporated in vacuo to an oil(8.48 g). Trituration with dry ether afforded monic acid as a whitesolid, which was collected and dried (2.62 g; 38%), m.p. 133°-135° C.(crystals from ethanol m.p. 146°-147° C.) (Found: C, 59.0; 8.2% C₁₇ H₂₈O₇ requires C, 59.3; H, 8.2%). Tlc revealed a single component Rf=0.44in chloroform, acetone, acetic acid 12:5:3 and a single peak by hplc[α]_(D) -13° (c, 1.0 EtOH) and -20° (c, 1.0 1% NaHCO₃), νmax (KBr) 3300,2960, 2950, 1690, 1640, 1450, 1250 cm⁻¹, λmax 221 nm (εm 11,200), δ_(H)(db-DMSO) 5.55 (1H,s,═CH), 2.05 ##STR15## and 0.80 (3H,d,>CHCH₃) δ_(C)(d⁶ -DMSO) (2 signals under the DMSO peaks) 167.3, 156.4, 117.6, 74.5,69.4, 68.2, 67.7, 64.6, 59.0, 54.6, 37.3, 31.47, 20.0, 18.4 and 11.6,m/e 227 (82%, M⁺ --H₂ O--C₅ H₇ O₂), 141 (43%) 111 (100%).

EXAMPLE 8 Sodium Monate

Monic Acid prepared in Example 7 (3.44 g; 1 mM) was suspended in water(10 ml). N/10 sodium hydroxide solution (10 ml; 1 mM) was added to thestirred suspension until complete solution was obtained (pH 7.5). Thelatter was freeze dried and finally dried in vacuo over P₂ O₅. (3.66 g;100%). [α]_(D) -20° (c,1.0 H₂ O) νmax (KBr) 3400, 2970, 1650, 1550cm⁻¹., λmax (EtOH) 214 nm (εm 14,600), δ_(H) (d⁶ -DMSO) 5.16 (1H,s,═CH), 1.95 (3H,s, ═CCH₃), 1.05 (3H,d,>CHCH₃) and 0.79 (3H,d,>CHCH₃).

EXAMPLE 9 Methyl4-[3R,4R-Dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoate(methyl monate)

Sodium monate prepared in Example 8 (1.12 g) was dissolved in drymethylformamide and 5 drops of hexamethylphosphoramide. Methyl iodide (5ml) was added and the reaction mixture was stirred overnight at roomtemperature. Evaporation to dryness in vacuo afforded a residue, whichwas partitioned between ethyl acetate and water and the ethyl layer wasseparated washed with sodium bicarbonate solution, brine, dried overmagnesium sulphate and evaporated to an oil (0.63 g). The latter wasdissolved in ether from which methyl monate crystallised (0.45 g; 50%)mp. 124°-125° (no depression of mixed m.p. was observed with authenticmaterial from example 3).

EXAMPLE 10 Preparation of Ethyl Monate

The sodium monate (0.80 g) was dissolved in N,N-dimethylformamide (7.5ml) and hexamethylphosphoramide (7 drops) then treated with ethyl iodide(1 ml) and stirred at room temperature for 24 hours. After evaporationto dryness, the oil was dissolved in ethyl acetate and washed withsodium bicarbonate and brine. The solution was dried (MgSO₄) andevaporated to an oil which crystallised on standing. Then the productwas filtered and washed with ether (0.55 g, 68%) m.p. 96°-7° C.,spectroscopically and chromatographically identical with materialdescribed in example 2.

EXAMPLE 11 Preparation of Methoxycarbonylmethyl4-[3R,4R-dihydroxy-5S(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoate(Methoxycarbonylmethyl monate)

Sodium4-[3R,4R-dihydroxy-5S(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoate(1.098 gm; 3.0 mM) was dissolved in dry dimethylformamide (15 ml) andhexamethylphosphoramide (15 drops). Methyl bromoacetate (0.918 gm; 6.0mM) was added and the reaction mixture stirred at room temperature foreighteen hours. The solvent was then removed at reduced pressure and theresidue partitioned between ethyl acetate and saturated sodiumbicarbonate solution. The organic layer was washed with brine and driedover anhydrous magnesium sulphate. Removal at reduced pressure gave ayellow oil (1.983 gm). This oil was purified by column chromatographyover silica gel (Type 60; 80 gm). Elution with 5% methanol/chloroformafforded the pure methoxycarbonylmethyl monate (by tlc and hplc) as acolourless oil, which on trituration with dry diethyl ether gave a whitesolid (0.580 gm; 46.5%). M.pt. 89°-91° C. (Found: C, 57.45; H, 7.85. C₂₀H₃₂ O₉ requires: C, 57.68; H, 7.74%). [α]_(D) ²⁰ =-8.22° (c,1% CHCl₃)λmax (EtOH) 225 nm (13,600). νmax (CHBr₃) 3450, 1745, 1723 and 1645cm⁻¹. δ_(H) (CDCl₃) 5.80 (1H,s, --CH═C); 4.57 (2H,s, CO₂ CH_(2L) CO₂);3.70 (s,CO₂ CH₃); 2.18 ##STR16## 1.19 (3H,d,J=6.7 Hz, CH₃ --14); 0.90(3H,d,J=6.7 Hz, CH₃ --17), δ_(C) (CDCl₃) 169.0, 165.6, 159.7, 116.2,74.8, 71.3, 70.4, 68.8, 65.4, 61.3, 60.0, 55.5, 52.2, 42.8, 39.5, 31.6,20.8, 19.4, 12.6. m/e 227.1318(35%), 125(12%; 227 --C₅ H₁₀ O₂), 111(70%)69(100%), no M⁺.

EXAMPLE 12 Preparation of4-Methoxycarbonylbutyl-4-[3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoate(4-Methoxycarbonylbutyl monate)

The sodium salt of4-[3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoicacid (0.50 gm; 1.366 mM) was dissolved in dry dimethylformamide (15 ml)and stirred at room temperature for eighteen hours with methyl5-bromovalerate (0.533 gm; 2.732 mM) and hexamethylphosphoramide (15drops). The solvent was then removed at reduced pressure and the residuepartitioned between ethyl acetate and saturated sodium chloride solutionand dried over anhydrous magnesium sulphate. Filtration and removal ofthe solvent at reduced pressure gave a pale yellow oil, which partiallysolidified on standing (0.810 gm). The product was purified by columnchromatography over silica gel (Type 60; 30 gm). Elution with 5%methanol/chloroform gave the pure 4-methoxycarbonylbutyl monate (by tlcand hplc) as a colourless oil, which on trituration with diethyl etheryielded a white solid (0.377 gm; 60%). M.pt. 75°-76° C. (ethylacetate/petroleum ether 40-60). (Found: C, 60.16; H, 8.31; C₂₃ H₃₈ O₉requires: C, 60.25; H, 8.35%). [α]_(D) ²⁰ -8.88° (c, 1% CHCl₃). νmax(KBr) 3460, 1735, 1710 and 1640 cm⁻¹. δ_(H) (CDCl₃) 5.72 (1H,s,CH═C);3.64 (3H,s,CO₂ CH₃); 2.18 ##STR17## 1.20 (3H,d,J=7.6 Hz, >CHCH₃); 0.92(3H,d,J=7.6 Hz, >CHCH₃); δ_(C) (CDCl₃) 173.9, 166.7, 157.3, 117.3, 74.8,71.0, 70.3, 68.9, 65.4, 63.2, 61.1, 55.6, 51.5, 42.8, 39.6, 33.5, 31.6,28.1, 21.5, 20.7, 19.1, 12.6, m/e440 (0.8%; M⁺ --H₂ O), 356 (0.9%; --C₅H₁₀ O₂), 327 (0.8%; --O(CH₂)₄ CO₂ CH₃), 309 (2%; 327--H₂ O), 227 (35%),214 (5%), 209 (5%), 125 (10%), 115 (100%), 111 (43%).

EXAMPLE 13 Preparation of 10-Methoxycarbonyldecyl4-[3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoate(10-Methoxycarbonyldecyl monate)

The sodium salt of4-[3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoicacid (0.750 gm; 2.05 mM) was dissolved in dry dimethylformamide (25 ml)and stirred at room temperature for eighteen hours with methyl11-bromoundecanoate (1.145 gm; 4.10 mM) and hexamethylphosphoramide (25drops). The solvent was then removed at reduced pressure and the residuepartitioned between ethyl acetate and saturated sodium bicarbonatesolution. The organic layer was washed with saturated sodium solutionand dried over anhydrous magnesium sulphate. Filtration and removal ofsolvent at reduced pressure gave a pale yellow oil, which partiallycrystallised on standing (1.84 gm). Column chromatography over silicagel (Type 60; 75 gm), eluting with 5% methanol/chloroform gave the pure10-methoxycarbonyldecyl monate (hplc and tlc) as a colourless oil.Trituration with dry ether gave a white solid (0.619 gm; 56%). m.pt.75°-76° C. (ethyl acetate/hexane). (Found: C, 64.23; H, 9.47. C.sub. 29H₅₀ O₉ requires: C, 64.18; H, 9.29%). [α]_(D) ²⁰ -748° (c, 1% CHCl₃).λmax (EtOH) 222 nm (εm 13,400). νmax (CHBr₃) 3450, 1739, 1710 and 1645cm⁻¹. δ_(H) (CDCl₃) 5.70 (1H,s,CH═C); 3.61 (3H,s,CO₂ CH₃); 2.18(3H,s,CH₃ --C═C; 0.91 (3H,d,J═6. Hz CHCH₃). δ_(C) (CDCl₃) 174.4, 166.8,156.6, 117.7, 74.9, 70.4, 69.1, 65.9, 61.3, 55.6, 51.4, 42.8, 39.5,117.7, 34.1, 31.7, 29.2, 28.7, 26.0, 25.0, 20.8, 19.1, 12.7, m/e 524(1.5%; M⁺ --H₂ O), 440 (1%; --C₅ H₁₀ O₂), 327 (>5%, M⁺ --O(CH₂)₁₀ CO₂CH₃), 309 (2%; 327--H₂ O), 298 (22%; [H₂ C:C(CH₃).CH₂ CO₂ (CH₂)-₁₀ CO₂CH₃ ]⁺), 227 (100%), 209 (15%; 227--H₂ O), no M⁺.

EXAMPLE 14 Phenyl Monate

Isobutyl chloroformate (136 mgs) was added to an almost clear solutionof monic acid (344 mgs) in methylene chloride (10 ml) tetrahydrofuran (1ml) and triethylamine (10 mgs) with pyridine (1 drop) at -10° to 15° C.After stirring at ca -10° C. for 1/2 hour, phenol (188 mgs) was addedand reaction allowed to reach ambient temperature. The solution wasevaporated to dryness and residue dissolved in ethyl acetate/water.Separation of organic layer washing with water (pH 10.5, twice) thenbrine and evaporation after drying (MgSO₄) yielded an oil. The oil waschromatographed on silica gel (20 g) eluting with gradient ofmethanol/chloroform 2% to 5%. Fractions containing pure phenyl monate(by tlc and hplc) were collected and evaporated to an oil (260 mgs,62%), [α]_(D) ²⁰ -15.1° (c, 1.0 CHCl₃), λmax (EtOH) 227 (εm 14,100)nm,νmax (CHCl₃ ) 3,400 (broad, OH's), 1730 (broad, C═O's), 1645 and 910cm⁻¹, δ_(H) (CDCl₃) 6.9-7.5 (5H,m, Ph ), 5192 (1H,s,CH═C), 2.67##STR18## 0.88 (3H,d,J=8 Hz, CH-CH₃), δ_(C) (CDCl₃) 164.9, 160.4, 150.6,129.3, (two signals), 125.6, 121.7 (two signals), 116.5, 74.8, 71.2,70.2, 68.9, 65.4, 61.3, 55.6, 43.1, 42.8, 39.6, 31.6, 20.8, 19.4, 12.7.

EXAMPLE 15 p-Methoxycarbonylphenyl monate

Isobutyl chloroformate (136 mgs) was added to a solution of monic acid(244 mgs) and triethylamine (101 mgs) in THF (15 ml) at -10° to -15° C.After stirring for 1/2 hour at ca -10° C. a solution of methylp-hydroxybenzoate (340 mgs) in THF (1 ml) was added and the reactionstirred for 1 hour at 0° C. then 1 hour at room temperature. Filtrationand evaporation yielded an oil which was dissolved in ethyl acetate,washed with sodium bicarbonate and brine then dried (MgSO₄). Evaporationyielded an oil which was chromatographed on silica (20 g) eluting withgradient of methanol/chloroform 0-5%. Fractions containing pure product(by tlc, hplc) were collected and evaporated to an oil (325 mgs, 68%),[α]_(D) ²⁰ =19.1° (C,1.0 CHCl₃), λmax (EtOH) 241 (ε20,763)nm, νmax(CHCl₃) 3,400 (broad), 1720 (broad), 1282 and 1110 cm⁻¹, δ_(H) (CDCl₃)7.97 ##STR19## 5.92 (1H,s,CH═C), 3.85 (3H,s,OCH₃), 2.23 ##STR20## 1.18(3H,d,J=6 Hz, CHCH₃), 0.88 (3H,d,J=6 Hz,CHCH₃), δ_(C) (CDCl₃) 166.6,164.2, 161.6, 154.5, 131.1 (two signals), 127.3, 121.8 (two signals),116.2, 74.8, 71.2, 70.3, 68.9, 65.5, 61.2, 55.7, 52.2, 43.2, 42.8, 39.7,31.6, 20.7, 19.5, and 12.7.

EXAMPLE 16 3-Pyridyl monate

A solution of monic acid (172 mgs) in THF (10 ml) and triethylamine (69μl) at -10° to -15° C. was treated with isobutyl chloroformate (65 μl)and pyridine (1 drop). The reaction was stirred for 1/2 hour at ca. -10°C. then a solution of 3-hydroxypyridine (95 mgs) in THF (1 ml) andtriethylamine (140 ml) was added. After stirring at 0° C. for 1 hour and1 hour at room temperature the reaction mixture was evaporated to anoil, dissolved in ethyl acetate/water and the organic layer washed withsodium bicarbonate then brine. Evaporation to dryness yielded an oilwhich was chromatographed on silica (10 g) eluting with a gradient ofmethanol/chloroform 0 to 5%. Fractions containing pure product (by tlc,hplc) were collected and evaporated to an oil (83 mgs; 39%), [α]_(D) ²⁰=-18.8° (C,1.0 CHCl.sub. 3) λmax (EtOH) 231 (ε 13.000)nm, (1H,m,pyridyl6-H) 3400(broad), 1642 and 1120 cm⁻¹ ; δ (CDCl₃) 8.35 (1H,s,pyridyl2--H), 5.94 (1H,s,CH═C), 2.23 ##STR21## 1.18 (3H,d,CHCH₃), 0.90(3H,d,CHCH₃) 164.1, 162.2, 147.6, 146.3, 143.5, 129.7, 124.0, 115.8,74.8, 71.3, 70.4, 71.3, 70.4, 68.9, 65.5, 61.3, 55.6, 43.3, 42.9, 39.8,31.6, 20.8, 19.6, and 12.7.

EXAMPLE 17 4-Coumaryl monate

Isobutyl chloroformate (65 ml) was added to a solution of monic acid(172 mgs) and triethylamine (69 μl) in THF (8 ml) at -10° C. followed bypyridine (1 drop). After half an hour at -5° to -10° C., a solution of4-hydroxycoumarin (162 mgs) in THF (2 ml) and triethylamine (140 μl) wasadded and reaction stirred at 0° C. for 1 hour then room temperature for1 hour. The reaction mixture was evaporated to dryness. The residue waspartitioned between ethyl acetate and water and the organic layer washedwith sodium bicarbonate and brine. After drying (MgSO₄) the solution wasevaporated to an oil and chromatographed on silica (10 g) eluting withgradient of methanol/chloroform 2-5%. Fractions containing pure product(by tlc) were collected and evaporated to an oil (130 mgs, 53%), [α]_(D)²⁰ =13.0° (c,1.0 CHCl₃ ) νmax 3400 (broad, OH's), 1755, 1720 (C═O'S) and1620 cm⁻¹, δ_(H) (CDCl₃) 7-7.7 (4H,m, C₆ H₄) 6.45 (1H,s,COCH═). 6.00(1H,s,CH═C), 2.27 (3H,s,CH₃ -C═C), 1.18 (3H,d,CH₃ -CH), 0.90 (3H,d,CH₃-CH), δ_(C) (CDCl₃) 165.4, 162.2, 161.6, 159, 153.6, 132.7, 124.4,123.1, 116.9, 116.2, 115.8, 114.9, 104,4, 74.8, 71.4, 70.3, 68.8, 65.6,61.3, 55.6, 43.5, 42.8, 39.8, 31.6, 20.8, 19.9, 20.7.

EXAMPLE 18 α R,S, Methoxycarbonylbenzyl monate

Methyl α-bromophenylacetate (390 mgs; 1.70 mM) was added to a solutionof sodium monate (311 mgs; 0.85 mM) in dry dimethylformamide (10 ml)containing hexamethylphosphoramide (10 drops) and the solution wasstirred at room temperature for 23 hours. The reaction mixture wasevaporated to dryness and the resulting oil was dissolved in ethylacetate. The latter was washed with sodium bicarbonate solution, brine,dried over magnesium sulphate. Filtration and removal of the solvent invacuo afforded an oil (710 mg), which was chromatographed over silicagel (Type 60; 28 g) eluting with a gradient from chloroform to 8%methanol/chloroform to give α R,S-Methoxycarbonylbenzyl monate 310 mgs)(72%) as a white foam (pure by tlc and hplc). [α]_(D) ²⁰ =1.8 (c,1.0CHCl₃). λmax (EtOH) 223 nm (εm 18,300), νmax (CHCl₃) 3400, 2950, 1750,1720, 1640, 1500, 1450, 1430 cm⁻¹, δH (CHCl₃) 7.3 ##STR22## 5.88(1H,s,αCH), 5.84, (1H,s,CH═C), 3.65 (3H,s,CO₂ CH₃), 2.18, ##STR23## 1.18(3H,d, CH₃ -14) and 0.88 (3H,d,CH₃ -17), δ_(c) (CDCl₃) 169.9, 165.6,159.8, 129.1, 128.8, 127.7, 116.4, 74.9, 73.9, 71.4, 70.3, 68.9, and68.7, 65.4, 61.3, 55.5, and 55.3, 52.6, 42.8, 42.7, 39.5, 31.6, 20.8,19.6, 19.3, and 12.7, m/e 492 (M+), 227 (3%), 107 (100%). (Found:M=492.2436, C₂₆ H₃₆ O₉ requires 492.2360).

EXAMPLE 19 1 R,S-Methoxycarbonylethyl monate

Methyl 2-bromopropionate (167 mg; 1 mM) was added to a solution ofsodium monate (183 mg, 0.5 mM) in dry dimethylformamide (5 ml)containing hexamethylphosphoramide (5 drops) and the solution wasstirred at room temperature for 17 hours. The reaction mixture wasevaporated to dryness and the resulting oil was dissolved in ethylacetate. The latter was washed with sodium bicarbonate solution, brine,dried over magnesium sulphate. Filtration and removal of the solvent invacuo afforded an oil (181 mg) which was chromatographed over silica gel(Type 60, 12 g) eluting with a gradient from chloroform to 6%methanol/chloroform to give 1 R,S--methoxycarbonylethyl monate (150 mg;70%) as an oil (pure by tlc and hplc.). [α]_(D) ²⁰ -11.6° (c,1.0CHCl₃).λmax (EtOH) 224 nm (εm 13,600), νmax (CHCl₃) 3400, 2950, 1750,1720, 1640, 1450, 1415 cm⁻¹, δ_(H) (CDCl₃) 5.78 (1H,s,CH═C), 5.05(1H,q,α-CH), 3.68 (3H,s, CO₂ CH₃) 2.16 ##STR24## 1.56 (3H,d,β-CH₃), 1.19(3H,d, CH₃ -14) and 0.90 (3H,d,CH₃ -17), δ_(c) (CDCl₃) 171.9, 165.7(split), 159.0, 116.7, 75.0, 71.3, 70.5 and 70.3, 69.0, and 68.9, 68.0,65.5, 61.3, 55.5 (split), 52.2, 43.1, and 42.8, 39.6, and 39.4, 31.7,and 31.5, 21.0 and 20.9, 19.5, and 19,3, 17.1 and 16.9 and 12.6, m/e 430(M⁺ <1%) 227 (42%), 111 (100%). (Found: M=430.2179, C₂₁ H₃₄ O₉ requires430.2203).

EXAMPLE 20 Preparation of 5-Methoxycarbonylpentyl4-[3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-3E-enoate.(5-methoxycarbonylpentyl monate)

The sodium salt of4-[3R,4R-dihydroxy-5S-(2S,3S-epoxy-5S-hydroxy-4S-methylhexyl)-2,3,5,6-tetrahydropyran-2S-yl]-3-methylbut-2E-enoicacid (0.8 gm; 2.19 mM) was dissolved in dry dimethylformamide (15 ml)and stirred at room temperature for 18 hours with methyl6-bromohexanoate (1.7 gm; 8.13 mM) and hexamethylphosphoramide (15drops). The solvent was then removed at reduced pressure and the residuepartitioned between ethyl acetate and saturated sodium bicarbonatesolution. The organic layer was washed with saturated sodium chloridesolution and dried over anhydrous magnesium sulphate. Filtration andremoval of the solvent at reduced pressure gave a pale yellow oil (1.72gm) which was purified by column chromatography over silica gel (35 gm;Type 60). Elution with 5% methanol/chloroform gave the pure5-methoxycarbonylpentyl monate (by tlc and hplc) as a colourless oil,which on trituration with diethyl ether yielded a white solid (0.250 gm;24%). M.pt. 59°-61° C. (found: C, 60.87; H, 8.37. C₂₄ H₄₀ O₉ requires:C, 61.00; H, 8.53%). [α]_(D) ²⁰ --8.94 (C, 1% CHCl₃), λmax (EtOH) 222 nm(εm 14,200)νmax (KBr) 3480, 1740, 1710, 1645 cm⁻¹. δ_(H) (CDCl₃) 5.69(1H,s,CH═C), 3.61 (3H,s,CO₂ CH₃); 2.17 ##STR25## 1.20 (3H,d,J=7.0 Hz,CH₃ --14); 0.91 (3H,d,J=6.0 Hz, CH₃ --17), δ_(C) (CDCl₃) 174.1, 166.8,157.0, 117.5, 74.9, 71.2, 70.3, 68.9, 65.4, 63.5, 61.2, 55.6, 51.6,42.8, 39.6, 33.9, 31.6, 28.4, 25.6, 24.6, 20.7, 19.1 and 12.7 m/e454.2610 (0.6%; M⁺ --H₂ O; C₂₄ H₃₈ O₈ requires 454.2567), 227 (42%), 129(50%), 111 (61%).

EXAMPLE 21. 1R,S-Methoxycarbonyl-1R,S-cyclohexylmethyl monate

Sodium monate (0.80 gm; 2.19 mM) was dissolved in dry dimethylformamide(15 ml) and hexamethylphosphoramide (15 drops). Methyl2-bromo-2-cyclohexyl acetate (1.91 gm; 8.13 mM) was added and thereaction mixture stirred at room temperature for 64 hours. The solventwas then removed at reduced pressure and the residue partitioned betweenethyl acetate and saturated sodium bicarbonate solution. The organiclayer was washed with brine and dried over anhydrous magnesium sulphate.Removal of the solvent at reduced pressure gave a yellow oil, which waspurified by column chromatography over silica gel(Type 60. 17 gm).Elution with 5% methanol/chloroform afforded the pure1R,S-methoxycarbonyl-1R,S-cyclohexylmethyl monate (by tlc and hplc) as awhite foam (0.175 gm; 16%). [α]_(D) ²⁰ -6.2° (C,1%CHCl₃), λmax (EtOH)224 nm (εm 13,800), νmax (KBr) 3440, 1745, 1720, and 1645 cm⁻¹. δ_(H)(CDCl₃) 5.80 (1H,s,CH═ C); 4.79 (1H,d,J=4.0 Hz, CO₂ CH); 3.69 (3 H,s,CO₂CH₃); 2.18 ##STR26## 1.20 (3 H,d,J=6.0 Hz, CH₃ --14); 0.90 (3H,d,J=7.0Hz, CH₃ -17), δ_(c) (CDCl₃) 170.8, 166.1, 158.8, 116.8, 76.1, 75.1,71.4, 70.5, 69.1, and 68.8, 65.5, 61.3, 55.6, and 55.4, 51.9 and 51.8,43.1, 42.9 and 42.8, 39.7, 29.1, 28.1, 26.0, 20.9, 19.6, and 19.2, 12.7and 12.6, m/e 254.1526 (2.5%, C₁₄ H₂₂ O₄ requires 254.1518), 227.1284(16%, C₁₂ H₁₉ O₄ requires 227.1283), 95 (85%), 90 (100%.

EXAMPLE 22 n-Octyl monate

Sodium monate (183 mgs) was dissolved in DMF (5 ml) and HMPA (1 drop)then sodium iodide (75 mgs) and n-bromooctane (0.2 ml) were added. Thesolution was stirred for 1 day then evaporated to dryness, dissolved inethyl acetate/water and organic layer washed with sodium bicarbonatesolution and brine. After drying (MgSO₄) the solution was evaporated toan oil which was chromatographed on silica (10 g) eluting with gradientof methanol/chloroform 0-5%. Fractions containing pure product (by tlc)were collected and evaporated to yield an oil (130 mgs, 57%), [α]_(D) ²⁰-10.2 (c,1.0 CHCl₃), νmax (CHCl₃) 3400 (broad, OH's). 1703 (C═O), 1645and 1150 cm⁻¹, δ_(H) (CDCl₃) 5.68 (1H,s,CH═C), 4.02 (2 H,t,OCH₂ CH₂),2.16 (3 H,s,CH₃ CH═C), 0.90 (3H,d,CHCH), δ_(C) (CDCl₃) 166.9, 156.6,117.7, 74.9, 71.4, 70.3, 69.0, 65.4, 64.0, 61.4, 55.6, 42.9 (twosignals), 39.5, 31.8, 31.6, 29.2 (two signals), 28.8, 26.0, 22.6, 20.8,19.1, 14.1, 12.7.

EXAMPLE 23 n-Butyl monate

Sodium monate (183 mgs) was dissolved in DMF (5 ml) and HMPA (1 drop)and treated with n-iodobutane (1 ml) then stirred at room temperatureovernight. The solution was evaporated to dryness dissolved in ethylacetate/water and the organic layer washed with sodium bicarbonate andbrine. After drying (MgSO₄) the solution was evaporated to an oil whichwas chromatographed on silica (10 g) eluting with gradient ofmethanol/chloroform 0-5%. Fractions containing pure product (by tlc)were collected and evaporated to yield an oil (124 mgs, 62%), [α]_(D) ²⁰-9.6° (c,1.0 CHCl₃), 3400 (broad, OH's), 1708 (C═O). 1650 and 1155 cm⁻¹,δ_(H) (CDCl₃) 5.69 (1H,s,CH═C), 4.03 (2H,t,OCH₂ (CH₂)₂), 2.16 (3H,s,CH₃C═C), 1.19 (3H,d,CH₃ --CH), 0.92 (5H,m,CH₃ CH and CH₃ (CH.sub. 2)₃),δ_(C) (CDCl₃) 167.0, 156.7, 117.7, 74.4, 71.3, 70.3, 69.0, 65.4, 63.6,61.3, 55.6, 42.9 (two signals), 39.5, 31.6, 30.8, 20.8, 19.2, 19.1,13.7, 12.7.

EXAMPLE 24 Prop-2-enyl monate

Sodium monate (0.300 gm; 0.82 mM) was dissolved in dry dimethylformamide(10 ml) and stirred at room temperature for 3 days with allyl bromide(0.199 gm; 1.64 mM) and hexamethylphosphoramide (10 drops). The solventwas then removed at reduced pressure and the residue partitioned betweenethyl acetate and saturated sodium bicarbonate solution. The organiclayer was washed with brine and dried over anhydrous magnesium sulphate.Filtration and removal of the solvent at reduced pressure gave a yellowoil (0.349 gm), which was purified by column chromatography over silicagel (Type 60; 14 gm). Elution with 5% methanol/chloroform gave the pureprop-2-enyl monate as a colourless oil (220 gm; 70%), [α]_(D) ²⁰ -11.4°(C, 1% CHCl₃), λ_(max) (EtOH) 223 nm (ε_(m) 13,800), ν_(max) (nujol)3,400. 1710, 1645 cm⁻¹. δ_(H) (CDCl₃) 5.6-6.1 (2H, m, --CH═C protons);5.05-5.5 CH₃ (2H, m, C═CH₂); 4.54 (2H, d, J=5.5 Hz, CO₂ CH₂); 2.18 (3H,s, C═C); 1.19 (3H, d, J=6.5 Hz, CH₃ --14); 0.91 (3H, d, J=7.0 Hz, CH₃--17). δ_(C) (CDCl₃) 166.3, 157.6, 132.6, 118.0, 117.2, 74.9, 71.3,70.3, 68.9, 65.4, 64.5, 61.3, 55.6, 42.8, 39.5, 31.6, 20.8, 19.2 and12.7.

EXAMPLE 25 1-Carboxymethyl monate sodium salt

1-Methoxycarbonylmethyl monate (0.225 gm; 0.54 mM) was dissolved inmethanol (22.5 ml) and pH10 sodium hydroxide/sodium bicarbonate buffersolution (22.5 ml) and stirred at room temperature for 18 hours. The pHwas then adjusted to 9 and the methanol was removed at reduced pressure.The aqueous solution was washed with ethyl acetate in order to removeany starting material. The aqueous solution was relayered with ethylacetate and the pH adjusted to 3.0 by the addition of 1 N hydrochloricacid. The organic layer was dried over magnesium sulphate, filtered andthe solvent removed to yield a colourless oil (0.170 gm). This oil wasdissolved in water by adjusting the pH to 7.0 by the addition of 0.1 Nsodium hydroxide solution. Freeze drying yielded the 1-carboxymethylmonate sodium salt as a white solid (0.150 gm; 65%). [α]_(D) ²⁰ -18.8°(C, 1% CH₃ OH),λ_(max) 222 nm (ε_(m) 11,600). ν _(max) (KBr) 3420, 1720and 1620 cm⁻¹. δ_(H) (CDCl₃) 5.90 (1H, s, --CH═C); 4.47 (2H, s, CO₂--CH₂ --CO₂); 2.15 ##STR27## 1.20 (3H, d, J=6.0 Hz, CH₃ --14); 0.93 (3H,d, J=7.0 Hz, CH₃ --17), δ_(C) (CDCl₃) 175.1, 167.4, 158.9, 116.4, 74.2,69.4 (split), 68.3, 64.8, 62.5, 61.2, 56.5, 41.7, 38.7, 30.8, 18.7,18.0, 10.9.

EXAMPLE 26 1-Carbamoylmethyl monate

Sodium monate (183 mgs) in DMF (5 ml) and HMPA (1 drop) was treated with2-chloroacetamide (95 mgs) and sodium iodide (150 mgs). After stirringovernight solution evaporated to dryness dissolved in ethylacetate/water and washed with sodium bicarbonate and brine solutions.The aqueous fractions were found to contain product (tlc) and werefreeze dried then extracted with methanol. The combined methanol andethyl acetate solutions were evaporated to dryness and residuechromatographed on silica (8 g) eluting with gradient ofmethanol/chloroform 0-4%. Fractions containing pure product (by tlc)were combined and evaporated to yield crystalline product (77 mgs, 36%),ν_(max) (CHCl₃) 3400 (broad, OH's), 1712 (C═O's) and 1650 cm⁻¹, δ_(H)(CDCl₃) 5.72 (1H, s, CH═C), 3.64 (2H, s, CH₂ CONH₂), 2.18 (3H, s, CH₃C═C), 1.20 (3H, d, CH₃ CH), 0.91 (3H, d, CH₃ CH).

EXAMPLE 27 3-Methoxycarbonylprop-2en-1-yl monate

Sodium monate (106 mgs) was dissolved in DMF (5 ml) treated with methyl4-bromocrotonate (0.2 ml) then stirred overnight at room temperature.The solution was evaporated to dryness, dissolved in ethyl acetate/waterand the organic layer washed with aqueous sodium bicarbonate and brine.After drying (MgSO₄) the solution was evaporated to dryness and the oilchromatographed on silica (4 g) eluting with gradient ofmethanol/chloroform 0-5%. Fractions containing pure product (by tlc)were collected and evaporated to an oil (17 mgs, 14%) ν_(max) (CHCl₃)3400 (broad, OH'S), 1718 (C═O's), 1670 and 1648 cm⁻¹, δ_(H) (CDCl₃) 6.92(1H, 2×m, J=16, CH₂ CH═CH--), 5.98 (1H, 2×m, J=16, CH₂ CH═CH), 5.77 (1H,s, CH═C), 4.72 (2H, m, CH₂ CH═CH) 3.70 (3H, s, CO₂ CH₃), 2.19 (3H, s,CH₃ C═C), 1.20 (3H, d, CH₃ CH), 0.91 (3H, d, CH₃ CH).

EXAMPLE 28 2,3-Epoxypropyl monate.

Sodium monate (0.267 gm; 0.73 mM) was dissolved in dry dimethylformamide(10 ml). Epibromohydrin (0.20 gm; 1.46 mM) and hexamethylphosphoramide(10 drops) were added and the solution stirred at room temperature for 3days. The solvent was then removed at reduced pressure and the residuepartitioned between ethyl acetate and saturated sodium bicarbonatesolution. The organic layer was washed with brine and dried overanhydrous magnesium sulphate. Filtration and removal of the solvent atreduced pressure gave a yellow oil (0.450 gm) which was purified bycolumn chromatography over silica gel (Type 60; 11 gm). Elution with 5%methanol/chloroform gave the pure (by hplc and tlc) 2,3-epoxypropylmonate as a colourless oil (0.240 gm; 83%), νmax (CH Br₃) 3450, 1715,1645, 1222 and 910 cm⁻¹, δ_(H) (CDCl₃) 5.76 (1H,s, CH═C); 4.15 (2H,2×AB,CO₂ CH); 2.20 ##STR28## 1.22 (3H,d, J=6.0 Hz, CH₃ --14); 0.92(3H,d,J=7.0 Hz, CH₃ --17). δ_(C) (CDCl₃) 166.2, 158.4, 116.8, 75.0,71.2, 70.4, 69.0, 65.5, 64.2, 61.2, 55.6, 49.6, 44.8, 42.9, 39.6, 31.7,20.8, 19.3, 12.6.

EXAMPLE 29 2-Propynyl monate

Sodium monate (0.267 gm; 0.73 mM) was dissolved in dry dimethylformamide(10 ml). Propargyl bromide (0.174 gm; 1.46 mM) andhexamethylphosphoramide (10 drops) were added and the solution stirredat room temperature for 16 hours. The solvent was then removed atreduced pressure and the residue partitioned between ethyl acetate andsaturated sodium bicarbonate solution. The organic layer was washed withbrine and dried over anhydrous magnesium sulphate. Filtration andremoval of the solvent at reduced pressure gave a yellow oil (0.390 gm),which was purified by column chromatography over silica gel (Type 60; 11gm). Elution with 5% methanol/chloroform gave the pure (hplc and tlc)2-propynyl monate as a colourless oil (0.225 gm; 81%) νmax (CHBr₃) 3420,2110, 1718 and 1645 cm⁻¹. δ_(H) (CDCl₃) 5.75 (1H,s, CH═C); 4.66(2H,d,J=3.0 Hz, CO₂ CH₂); 2.20 ##STR29## 1.20 (3H,d,J=6.5 Hz, CH₃ --14);0.92 (3H,d,J=6.5 Hz, CH₃ --17), δ_(C) (CDCl₃) 165.6, 158.9, 116.5, 78.3,75.0, 74.6, 71.2, 70.4, 69.0, 65.5, 61.3, 55.6, 51.2, 42.9, 39.6, 31.7,20.8, 19.4, 12.7.

BIOLOGICAL DATA

(a) Tables 1 and 2 show the M.I.C. Values (μg/ml) for several compoundsof this invention against six Gram-positive organisms and againstN.gonorrhoae and H. influenzae.

(b) Table 3 gives the, in vitro antimycoplasmal activities of certainesters of monic acid in terms of their M.I.C. values.

                                      TABLE 1                                     __________________________________________________________________________               COMPOUND OF EXAMPLE NUMBER                                         Organism   10  9   6   11  13  12  14  15  16                                 __________________________________________________________________________    Bacillus subtilis                                                                        0.2 0.5 0.1 1.0 0.2 5.0 12.5                                                                               5.0                                                                              1.0                                Staph. aureus Oxford                                                                     0.2 0.5 0.2 1.0 1.0 2.5  5.0                                                                               5.0                                                                              1.0                                Staph. aureus                                                                 Russell    0.2 0.5 0.2 2.5 1.0 5.0 12.5                                                                              12.5                                                                              2.5                                Staph. aureus 1517                                                                       0.2 1.0 0.2 2.5 2.5 5.0 12.5                                                                              12.5                                                                              2.5                                Strep. faecalis I                                                                        >100                                                                              >100                                                                              >100                                                                              >100                                                                              >100                                                                              >100                                                                              >100                                                                              >100                                                                              >100                               Strap. pyogenes                                                               CN10       0.2 2.5 --  2.5 1.0 0.2 25  25  2.5                                N. gonorrhoae                                                                            0.02                                                                              0.1 NT  0.2 0.2 0.1 NT  NT  1.0                                H. influenzae                                                                            0.1 0.5 0.2 0.2 1.0 0.2 2.5 12.5                                                                              0.5                                __________________________________________________________________________     (NT = Not tested)                                                        

                                      TABLE 2                                     __________________________________________________________________________               COMPOUND OF EXAMPLE NUMBER                                         Organism   17  18  19  20  21  22  23  24                                     __________________________________________________________________________    B. subtilis                                                                              5.0 2.5 1.0 0.1 5.0 0.5 0.1 0.2                                    S. aureus Oxford                                                                         5.0 5.0 1.0 0.2 10  0.5 0.2 0.2                                    S. aureus Russell                                                                        10  25  2.5 0.5 25  2.5 0.5 0.5                                    S. aureus 1517                                                                           25  25  5.0 0.5 50  2.5 1.0 1.0                                    Strep. faecalis I                                                                        >100                                                                              >100                                                                              >100                                                                              >100                                                                              >100                                                                              >100                                                                              50  50                                     Strep. pyogenes GpA                                                                      50  25  25  0.5 25  2.5 1.0 2.5                                    N. gonorrrhoae                                                                           NT  NT  NT  0.1 NT  NT  0.5 NT                                     H. influenzae                                                                            2.5 5.0 1.0 0.1 25  2.5 0.1 0.1                                    __________________________________________________________________________     (NT = Not tested)                                                        

                                      TABLE 3                                     __________________________________________________________________________     The antimycoplasmal activities of esters of monic acid                       M.I.C. (μg/ml)                                                                        Example                                                                            M. gallisepticum                                                                      M. suipeumoniae                                                                       M. dispar                                                                          M. pneumoniae                            Compound   No   56      (Laber) H225 429A                                     __________________________________________________________________________    Methyl monate                                                                             9   1.5     <0.5    <0.5 0.6                                      Benzyl monate                                                                            6    <0.5    <0.5    <0.5 250                                      Methoxycarbonyl-                                                              methyl monate                                                                            11   >250    >250    250  >250                                     4-Methoxycarbonyl                                                             butyl monate                                                                             12   250     15.6    1.0  125                                      10-Methoxycarbonyl-                                                           decyl monate                                                                             13   15.6    31.25   1.0  15.6                                     __________________________________________________________________________

Improved Isolation of Monic Acid.

Pure Crystalline pseudomonic acid (1.00 gm; 2 mM) was dissolved intrimethylorthoformate (10 ml) and stirred at R.T. for 30 minutes withp-toluene sulphonic acid (10 mg). The solvent was then removed atreduced pressure and the residual oil immediately dissolved in 1 N NaOH(10 ml; 10 mM). The solution was stirred at 65° C. for 3 hours, thencooled and the pH adjusted to 7.0 with conc. HCl. Methanol (10 ml) wasadded, the pH was adjusted to 2.0 with 5 N HCl and the solution wasstirred at R.T. for 15 minutes. The pH was then raised to an maintainedat 9.0-9.5 with NaOH for 3 hours, when HPLC indicated completehydrolysis of the O-formate. The pH was adjusted to 7.0 and the solutionevaporated to dryness at reduced pressure. The residual solid wasdissolved in water (20 ml), saturated with NaCl, layered with ethylacetate and acidified to pH 3. The organic layer was separated and theaqueous layer further extracted with 5×50 ml ethyl acetate. The combinedorganic extracts were dried over anhydrous MgSO₄ and the solvent removedat reduced pressure to yield a yellow oil (1.377 gm; 1433/50/l.)Trituration with dry diethyl ether gave the monic acid (>90% pure byHPLC and TLC) as a white solid (0.393 gm; 1433/50/2). A further 0.146 gm(1433/50/3) white solid was obtained from the mother liquors. Totalyield=0.539 gm (78%). M. pt. 130°-133° C. The product was identical toauthentic monic acid by HPLC and TLC (chloroform/acetate/acetic acid50:50:7).

What we claim is:
 1. A compound of the formula: ##STR30## wherein R is aheterocyclic ring system comprising oxygen, nitrogen or sulfur as thehetero atom and containing six ring members in the hetero ring, saidsystem being a monocyclic or a fused benzo bicyclic system and beingunsubstituted or substituted with a member selected from the groupconsisting of alkyl of 1 to 6 carbon atoms, carbalkoxy of 1 to 6 carbonatoms in the alkoxy group, phenyl and oxo.
 2. A compound of the formula:##STR31## wherein R is 2-oxo-4H-chromen-4-yl,2-oxo-4-methyl-2H-chromen-7-yl, 2-methyl-4-xo-4H-chromen-7-yl,2-phenyl-4-oxo-4H-chromen-7-yl, 2-oxo-4-carbethoxy-2H-chomen-7-yl,2-carbethoxy-4-oxo-4H-chromen-7-yl, quinol-8-yl, 2-pyridyl, 3-pyridyl,or 4-pyridyl.
 3. A compound according to claim 2 wherein theconfiguration about the depicted double bond is E.
 4. A compoundaccording to claim 2 wherein R is 2-pyridyl, 3-pyridyl, or 4-pyridyl. 5.The compound according to claim 2 wherein R is 3-pyridyl.
 6. Thecompound according to claim 2 wherein R is 2-oxo-4H-chromen-4-yl.